chore: add unit tests to pod webhook

[RealAnna]

This PR

• removes bug from annotation filter
• adds unit tests to admission webhook
• moved component test to a different file, put unit test in pod_webhook_test.go

Related Issues

#394

[codecov]

Codecov Report

Merging #419 (5f847d1) into main (8624958) will increase coverage by 44.48%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##             main     #419       +/-   ##
===========================================
+ Coverage   36.25%   80.74%   +44.48%     
===========================================
  Files          12       12               
  Lines         855      857        +2     
===========================================
+ Hits          310      692      +382     
+ Misses        530      136      -394     
- Partials       15       29       +14     

Impacted Files	Coverage Δ
webhooks/pod_webhook.go	89.22% <100.00%> (+89.22%)	⬆️

... and 2 files with indirect coverage changes

Flag	Coverage Δ
component-tests	84.86% <100.00%> (?)
unit-tests	56.24% <100.00%> (+19.98%)	⬆️

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